Final answer:
Without access to specific empirical data from the study on blood pressure changes due to the new drug, it is not possible to provide a correct point estimate from the options given.
Step-by-step explanation:
A point estimate for the true difference in blood pressure after taking a new drug. In statistical analysis, the point estimate is used to infer a population parameter based on sample data. In clinical trials or medical studies, the point estimate usually refers to the mean change in a measured variable, such as blood pressure.
However, to provide a specific numeric answer a, b, c, or d to the student's question, there must be access to detailed empirical data from the study that is referenced in the question, which includes the measurements of blood pressure before and after taking the medication for each subject. As no such data was provided in the student's question, we cannot definitively provide a correct point estimate answer. The student should ensure all necessary information is available in order to calculate or determine a point estimate for blood pressure differences.